With conventional techniques, in order to pick workpieces transferred in a single row by a conveyor, and to transfer the workpieces to multiple picking destinations according to a predetermined rule, a workpiece picking system is known, wherein multiple picking robots are installed at intervals in the workpiece transfer direction of the conveyor to pick-up and convey the workpieces arranged on the conveyor to the picking destinations by performing line tracking that makes each robot to follow the movement of the conveyor (see PTL 1, for example).